velia: update for the IPv4 hotfix

Change-Id: I93ac37ba12dcd950d993de29e197a954ff5cb112
Depends-on: https://cesnet-gerrit-czechlight/c/CzechLight/velia/+/4069
Depends-on: https://cesnet-gerrit-public/c/CzechLight/velia/+/4069
Depends-on: https://gerrit.cesnet.cz/c/CzechLight/velia/+/4069
diff --git a/submodules/velia b/submodules/velia
index 0541736..84575e0 160000
--- a/submodules/velia
+++ b/submodules/velia
@@ -1 +1 @@
-Subproject commit 0541736dd925f3566225057a216896d2aa46b983
+Subproject commit 84575e0012ab252e5b70524f8395f10e96e17f5a